How to solve it . Urgent

Dear Student,
(i)

Time in hours	Students
Less than 10	8
Less than 20	24
Less than 30	50
Less than 40	70
Less than 50	100
Less than 60	140
Less than 70	160
Less than 80	178
Less than 90	194
Less than 100	200

So upto 25 hours number of students, = 50
(ii) 

Time in hours	Students
More than 0	200
More than 10	192
More than 20	176
More than 30	150
More than 40	130
More than 50	100
More than 60	60
More than 70	40
More than 80	22
More than 90	6